Minor changes to proguard rules

app/proguard.cfg

@@ -71,8 +71,6 @@
 -dontwarn android.support.v7.**
 -dontwarn com.google.android.wearable.**
 
--keepattributes *Annotation*
-
 -keep class org.shredzone.flattr4j.** { *; }
 -dontwarn org.shredzone.flattr4j.**
 
@@ -94,6 +92,7 @@
 -keepclassmembers class ** {
     public void onEvent*(**);
 }
+-keep class de.danoeh.antennapod.core.event.*
 
 # android-iconify
 -keep class com.joanzapata.** { *; }